Officials: More smoke rises from Japan's crippled nuke-plant

(AP) - Smoke billowed from a building at Japan'scrippled nuclear power plant Friday as emergency crews worked toreconnect electricity to cooling systems and spray more water onthe overheating reactors at the tsunami-ravaged facility.

Four of the troubled Fukushima Dai-ichi plant's six reactorshave seen fires, explosions or partial meltdowns in the week sincethe tsunami. While the reactor cores where energy is generated area concern, Japanese and U.S. officials believe a critical dangerare the pools used to store spent nuclear fuel: fuel rods in onepool were believed to be at least partially exposed and in dangerof leaking radiation.

Friday's smoke came from Unit 2, and its cause was not known,the nuclear safety agency said. An explosion had hit the buildingon Tuesday, possibly damaging a crucial cooling chamber that sitsbelow the reactor core.

More urgent, Japan's chief government spokesman said, was theadjacent Unit 3. Fuel rods there may have been partially exposed,and without enough water, the rods may heat further and possiblyspew radiation. Frantic efforts were made Thursday to douse theunit with water, using helicopters and firetrucks, and authoritiesprepared to repeat the effort Friday.

In the week since the massive earthquake and tsunami, Japan'sgovernment and the utility that runs Fukushima have struggled tocontain the plant's cascading troubles.

Chief Cabinet Secretary Yukio Edano said Friday that Tokyo is asking the U.S. government for help and the two are discussing the specifics. The U.S. and Japan, close allies, have offered differingassessments over the dangers at Fukushima in recent days. U.S.Nuclear Regulatory Commission Chairman Gregory Jazcko said inWashington Thursday that it could take days and "possibly weeks"to get the complex under control. He defended the U.S. decision torecommend a 50-mile (80-kilometer) evacuation zone for itscitizens, wider than the 30-mile (50-kilometer) band Japan hasordered.

Crucial to the effort to regain control over the Fukushima plantis laying a new power line to the plant, allowing operators torestore cooling systems to the reactors. The operator, TokyoElectric Power Co., missed a deadline late Thursday but said Fridayworkers hoped to complete the effort, first reconnecting Unit 1.

Also Friday, the Group of Seven major industrialized countriesagreed to support Japan - whose infrastructure and industries werebadly battered by the disasters - by intervening in currencymarkets. The group did not say what it would do but the effortswould likely focus on weakening the Japanese yen, which has risenthis week. A strong yen could make Japanese exports lesscompetitive, crimping any recovery.

The quake and unfolding nuclear crisis have led to powershortages in Japan, forced auto and other factories to close,sending shockwaves through global manufacturing and trade, andtriggered a plunge in Japanese stock prices.